Automatic Watershed delineation

[Naveed Ahmed]

Dear Community,

I am using ArcSWAT since last 3 years. Now I am facing problem in another watershed delineation.

Actually, my watershed area is 190,000 km^2 with elevation ranges from 300-8000 meter and I am using DEM 30x30 meter resolution with total size of dem in 1.8 GB. 

In water delineation step it proceed only upto 57% and stop working....and I left it to do it completely but after  8/9 hours it was still at 57%. 

When I see the ArcGIS in the task manager of my computer....it shows ArcGIS is not responding.... 

why?

Is the size of DEM is high?

Or I have to use QGIS with QSWAT?

Any expert opinion.... thanks in anticipation.

[Natalja C.]

Hello,

8/9 hours is too little time for such a task. Depending on your machine, it will run anywhere from a couple of days to couple of weeks. Unless you are working on a workstation - just forget it :)

Other things to consider: how you foresee the calibration process of your model? How to you foresee the use of  such a model?

I can already tel you, that it will be nearly impossible to calibrate such a model (I mean to do a good calibration, ensuring all the processes are adequate, etc).

Next, the model runtime will be, most likely, several hours for ~10 years.

My advise, i) either use a coarser resolution (much coarser), ii) split your model in sub-models, iii) ditch the "standard" tools and use sciprs instead, or iv) brace yourself for a loooong wait on every step (not as long as some numerical models, but still.. I get inpatient and that is saying something ;) ) with an even longer and tedious calibration.

Best,

Natalja

[Naveed Ahmed]

Hi Natalija,

First of all many many thanks for a very detailed guidance.

I am using ArcSWAT since three years and I am familiar with ArcSWAT. I have already simulated the ArcSWAT for a river basin with 1.69x10^6 km^2 and it didn’t not take much time. The reason is DEM was coarse resolution. 

I am using a workstation of DELL precision series i-5, 7th generation with 24 GB RAM. 

Thanks for your advice and I will surely use the coarse resolution DEM to complete this project.

Regards 

Naveed

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[Suraj Shah]

Yes Naveed bro ...may be your Dem has some problem...

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[Naveed Ahmed]

Hi dear,

I don’t think so. However I an trying to reduce the size of DEM using GEE. This way the resolution will remain same 30x30 and only size will reduce.

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[Suraj Shah]

Naveed bro 

I think you are from UCAS..let's talk in wechat

I will add you..

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[Naveed Ahmed]

Hi dear,

Yes, I am from UCAS. Do you know me 😊? If yes, plz add me on WeChat.

Thanks 

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